1. Technical Field
The present invention relates to a planetary roller reducer.
2. Description of the Related Art
An explanation will be made for a planetary roller reducer by the rolling drive of conventional rollers by referring to FIG. 11. The reducer is provided with an input shaft 104 fitted in a tightening manner so as to be in agreement with an output shaft 102 of a motor 101, a sun shaft 104a installed so as to be extended from the input shaft 104 and arranged at the rotating center of the reducer, a plurality of planetary rollers 113 arranged with each other at equal intervals so as to enclose the sun shaft 104a and in external contact with the sun shaft 104a, an elastic ring 105 fixed to a casing 106 of the reducer and in internal contact with a plurality of the planetary rollers 113, a trunnion-type carrier 108 supported on the casing 106 so as to rotate, to which a pin shaft 111 for supporting the planetary roller 113 so as to rotate is fixed, and an output shaft 108a installed so as to be extended from the carrier 108 to take out the rotation of the carrier 108 (for example, refer to Patent Document 1 listed below).
The reducer is provided with an input bearing 120 set between the casing 106 and the input shaft 104 to support the input shaft 104 so as to rotate and an inner bearing 121 set between the carrier 108 and the leading end of the sun shaft 104 to support the sun shaft 104a directly coupled to the input shaft 104 so as to rotate. The planetary roller 113 is supported by the pin shaft 111 so as to rotate via a planetary roller bearing 122. The reducer is also provided with a pair of ball bearings 130 set between an inner boss of the casing 106 and the output shaft 108a to support the output shaft 108a so as to rotate.
Further, in order to prevent a side slip of the planetary roller 113 (that is, an axial slip), the reducer is provided on the sun shaft 104a with collars 104b, 104c for suppressing a lateral movement of the planetary roller 113.
Still further, a flange 109 for fixing the motor 101 to the casing 106 is formed on the casing 106 in such a manner that a socket portion 101a of the motor 101 is fitted inside. In order to fix the motor 101 to the casing 106, the output shaft 102 is fitted into a fitting hole of the input shaft 104 and the socket portion 101a is also fitted into the flange 109, thereby temporarily fixing the motor 101 to the casing 106 with screws (not illustrated). Then, the output shaft 102 is relatively positioned to the input shaft 104 to fit them in a tightening manner. Thereafter, the screws are tightened to fix the motor 101 to the casing 106, while care is taken so as not to influence the positional relationship between the output shaft 102 and the input shaft 104.    PATENT DOCUMENT 1: Japanese Unexamined Patent Application, First Publication No. H06-307512